Wouldn't they have to be fairly wealthy to be covering themselves in Woad all the time?

Makes more sense to me that they ate silver for its' health benefits (back then slver was probably just sticking out of the ground) and became blue as a result.

I think it might be plausible to conclude that these people who featured as gods and hero's may have been "wealthy". (Access to trade)

Incidentally, an Egyptian Mummie was discovered with blue dye which was originally believed to have been Indigo, but closer examination revealed it was Woad. (Tutankhamun we already know had R1b Haplogroup)

The R1b Haplogroup has the highest rate of lactose tolerance, leading to an educated guess, that this group was the first to domesticate cattle and consume dairy produce.
The interesting point is that cattle also have holy status in Indian as well as in other cultures from the Minoans to the Egyptians, (Apis the bull god).

The fact that R1b and associates migrated south during the great thaw is documented.

Pure R1b produces no melanin.
(Due to being wrapped in hides for 1000's of years.)